The trick to getting any spinner to last, wether it be aluminum, plastic or carbon fiber; is to avoid those spinner-first landings. A spinner, no matter what it's made of will not 'protect' your engine in a crash. A strong spinner may absorb some of the energy, but let's face it, if your engine went in at full throttle, you likely bent the shaft or worse.

I agree that aluminum spinners are better than plastic and, in most cases better than carbon, but they do not always limit damage to your plane in a crash.

I have some aluminum spinners up to 4 1/2 inches in diameter and let me tell you....crash protection ain't the reason. They are mostly just for looks...and they are very expensive to boot.